Based on a blended criteria of range, power, diversity, popularity, influence and my own bit of bias
Let the debate begin!1. Freddie Mercury (Queen)
2. Robert Plant (Led Zeppelin)
3. Ronnie James Dio (Dio / Black Sabbath / Rainbow)
4. Chris Cornell (Soundgarden / Audioslave)
5. Steve Perry (Journey)
6. Rob Halford (Judas Priest)
7. Bruce Dickinson (Iron Maiden)
8. Janis Joplin
9. David Bowie
10. Axl Rose (Guns N' Roses)
11. Mick Jagger (The Rolling Stones)
12. Roger Daltrey (The Who)
13. Jeff Buckley
14. Elvis Presley
15. Paul Rodgers (Free / Bad Company)
16. Ian Gillan (Deep Purple)
17. Steven Tyler (Aerosmith)
18. Ozzy Osbourne (Black Sabbath)
19. Bon Scott (AC/DC)
20. Brian Johnson (AC/DC)
21. Jim Morrison (The Doors)
22. Alice Cooper
23. Iggy Pop (The Stooges)
24. Meat Loaf
25. Billy Joel
26. Robin Zander (Cheap Trick)
27. Sammy Hagar (Van Halen / Montrose)
28. David Lee Roth (Van Halen)
29. Klaus Meine (Scorpions)
30. Geddy Lee (Rush)
31. Stevie Nicks (Fleetwood Mac)
32. Pat Benatar
33. Grace Slick (Jefferson Airplane)
34. Debbie Harry (Blondie)
35. Joan Jett (The Runaways)
36. Chrissie Hynde (The Pretenders)
37. Elton John
38. Lou Gramm (Foreigner)
39. Doro Pesch (Warlock)
40. Karen Carpenter (The Carpenters)
41. Floor Jansen (Nightwish / After Forever)
42. Cristina Scabbia (Lacuna Coil)
43. Sharon den Adel (Within Temptation)
44. Simone Simons (Epica)
45. Amy Lee (Evanescence)
46. Hayley Williams (Paramore)
47. Lzzy Hale (Halestorm)
48. Taylor Momsen (The Pretty Reckless)
49. Courtney LaPlante (Spiritbox)
50. Tatiana Shmayluk (Jinjer)
51. Eddie Vedder (Pearl Jam)
52. Kurt Cobain (Nirvana)
53. Scott Weiland (Stone Temple Pilots / Velvet Revolver)
54. Mike Patton (Faith No More)
55. Maynard James Keenan (Tool / A Perfect Circle)
56. Trent Reznor (Nine Inch Nails)
57. Till Lindemann (Rammstein)
58. Serj Tankian (System of a Down)
59. Corey Taylor (Slipknot / Stone Sour)
60. M. Shadows (Avenged Sevenfold)
61. James Hetfield (Metallica)
62. Dave Mustaine (Megadeth)
63. Tom Araya (Slayer)
64. Phil Anselmo (Pantera)
65. Randy Blythe (Lamb of God)
66. Mikael Åkerfeldt (Opeth)
67. Devin Townsend
68. Hansi Kürsch (Blind Guardian)
69. Roy Khan (Kamelot / Conception)
70. Tommy Karevik (Kamelot / Seventh Wonder)
71. Russell Allen (Symphony X)
72. Geoff Tate (Queensrÿche)
73. James Dean Bradfield (Manic Street Preachers)
74. Kai Hansen (Gamma Ray / Helloween)
75. Tobias Sammet (Avantasia / Edguy)
76. Joacim Cans (HammerFall)
77. Ann Wilson (Heart)
78. Fabio Lione (Rhapsody of Fire)
79. Roy Orbison
80. Buddy Holly
81. Layne Staley (Alice in Chains)
82. Little Richard
83. Chuck Berry
84. Jerry Lee Lewis
85. Fats Domino
86. Bo Diddley
87. Gene Vincent
88. Eddie Cochran
89. Rick Danko (The Band)
90. Levon Helm (The Band)
91. Richard Manuel (The Band)
92. Van Morrison
93. Rod Stewart (Faces)
94. Joe Cocker
95. Paul McCartney (The Beatles)
96. John Lennon (The Beatles)
97. George Harrison (The Beatles)
98. Liam Gallagher (Oasis)
99. Richard Ashcroft (The Verve)
100. Kelly Jones (Stereophonics)